1,166 research outputs found
Intersection Theory on Linear Subvarieties of Toric Varieties
We give a complete description of the cohomology ring of a
compactification of a linear subvariety of a torus in a smooth toric
variety whose fan is supported on the tropicalization of . It turns
out that cocycles on canonically correspond to Minkowski weights
on and that the cup product is described by the intersection product
on the tropical matroid variety .Comment: published versio
How do Ontology Mappings Change in the Life Sciences?
Mappings between related ontologies are increasingly used to support data
integration and analysis tasks. Changes in the ontologies also require the
adaptation of ontology mappings. So far the evolution of ontology mappings has
received little attention albeit ontologies change continuously especially in
the life sciences. We therefore analyze how mappings between popular life
science ontologies evolve for different match algorithms. We also evaluate
which semantic ontology changes primarily affect the mappings. We further
investigate alternatives to predict or estimate the degree of future mapping
changes based on previous ontology and mapping transitions.Comment: Keywords: mapping evolution, ontology matching, ontology evolutio
Master stability functions reveal diffusion-driven pattern formation in networks
We study diffusion-driven pattern-formation in networks of networks, a class
of multilayer systems, where different layers have the same topology, but
different internal dynamics. Agents are assumed to disperse within a layer by
undergoing random walks, while they can be created or destroyed by reactions
between or within a layer. We show that the stability of homogeneous steady
states can be analyzed with a master stability function approach that reveals a
deep analogy between pattern formation in networks and pattern formation in
continuous space.For illustration we consider a generalized model of ecological
meta-foodwebs. This fairly complex model describes the dispersal of many
different species across a region consisting of a network of individual
habitats while subject to realistic, nonlinear predator-prey interactions. In
this example the method reveals the intricate dependence of the dynamics on the
spatial structure. The ability of the proposed approach to deal with this
fairly complex system highlights it as a promising tool for ecology and other
applications.Comment: 20 pages, 5 figures, to appear in Phys. Rev. E (2018
From Tahrir Square to Open Space: Practical Experiences with Open Space Technology in Egypt
The Egyptian revolution started literally with an open space: at the Tahrir Square in the heart of Cairo. Here it was where many Egyptians for the first time in their lives made the experience of freely talking about politics in public. Since January 2011, many young Egyptians are trying to keep up this “Tahrir experience” by experimenting with new forms of political debate and civic education in Egypt. It was this spirit that resulted in the idea of introducing the Open Space Technology (OST) as a new format of civic education in Egypt. In March 2011 the authors of this article, both working in Egypt for many years, organized the first Open Space in the country. This event encouraged many other national and international institutions and initiatives to adopt and further develop OST in Egypt and other Arab countries. The unexpected popularity of OST in revolutionary Egypt proved that it is in fact the right methodology at the right time in the right context and the right place. OST is a meeting format that fosters dialogue and exchange in a democratic way. It is easy to organize and non-costly. It invites for sharing opinions, discovering common ground, discussing and tackling differences. It helps generating ideas and reflecting about their implementation. This article argues that Open Space (OS), therefore, is a format that perfectly fits the transforming political environment and the socio-cultural setting of Egypt and – most probably – other Arab transformation-states
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